Immunohistochemical expression of PD-L1 was evaluated in lung, gastrointestinal, breast, urothelial, and kidney tumors but also melanoma, head and neck, and hematologic cancers, using two scoring methods: the tumor proportion score (TPS) or tumor cell score (TC), representing the percentage of tumor cells with membranous positivity, irrespective of staining pattern and intensity, evaluated on at least 100 viable tumor cells, and the immune cell score (IC), representing the area occupied by PD-L1-positive immune cells relative to the entire tumor and peritumoral area. The gene discussed is CD274; the disease is melanoma.